Email authentication gives mailbox providers (like Gmail or Outlook) confidence that the messages they see from senders are authentic and not messages sent by a bad actor. The more confidence a mailbox provider has that the messages you send are legitimate, the more likely that provider is to deliver the message to the inbox. Full use of email authentication tools is best practice for email senders since spammers have become very smart about disguising malicious email under the veil of a trusted brand. Email authentication, or DMARC, gives mailbox providers (like Gmail or Outlook) confidence that the messages they see from senders are authentic and not messages sent by a bad actor. This framework is helpful when trying to prevent important emails from being flagged as spam or junk mail. Email authentication is a security technology that validates the identity of the mail server sending you mail. This is a fancy way of confirming that you are receiving emails from who you think you are receiving emails from, and not someone pretending to be them.
Difference between DomainKeys and DKIM :-
DKIM (DomainKeys Identified Mail): DomainKeys Identified Mail (DKIM) is an email security standard designed to make sure messages aren’t altered in transit between the sending and recipient servers. DKIM (DomainKeys Identified Mail) is a way for a sending server to “sign” emails as they leave its system, with the result being that emails will be verified more consistently throughout the internet. For example, if the DKIM signature on a message from my server passes verification on your server, then you will know that the message really did come from me and hasn’t been changed in transit. DKIM is a DomainKeys Identified Mail (DKIM) signing system, which allows your domain’s e-mail to be validated, and lets recipients know that they can trust the messages they receive from you.
DomainKey : DomainKeys is a new standard for validating the origin of email messages. DomainKeys utilizes public/private key encryption, DNS, and multiple policies to prove the legitimacy and contents of an email message. It verifies the domain used in the “From” or “Sender” header. If you already use DKIM, then DomainKeys is not only easy to implement, but it provides a wide range of capabilities that can extend your existing policy to include other domains, or sign both headers and bodies. Authenticate your domain-level e-mail messages with DomainKeys. It deploys public keys, domain names, and policies to authenticate the sender of an e-mail message. DomainKeys can be used at the top-level DNS of your company or organization. Every public key and policy record needs to be published in multiple authoritative servers. DomainKeys provides a mechanism for DKIM-aware email receivers to “learn” the public keys associated with an identity and to validate messages that have been signed by that domain.
Content Source :-https://medium.com/@aariyagoel5621/what-is-email-authentication-and-difference-between-domainkeys-and-dkim-fb1779845bcf
